Powder and a HIP:ed object and the manufacture thereof

Abstract

The present disclosure relates to a powder of an austenitic alloy and a HIP:ed object manufactured thereof and a process for the manufacturing the HIP:ed object and its use in corrosive environments.

The invention claimed is: 
     
       1. A powder, comprising an austenitic alloy having the following composition in weight %:
 C less than or equal to 0.03; 
 Si 0.1 to 0.5; 
 Mn 0.1 to 2.0; 
 P less than or equal to 0.04; 
 S less than or equal to 0.05; 
 Cr 26.7 to 28; 
 Ni 35 to 36; 
 Mo 6.1 to 6.7; 
 N 0.32 to 0.60; 
 Cu less than or equal to 0.4; 
 balance Fe and unavoidable impurities. 
 
     
     
       2. The powder according to  claim 1 , wherein the content of Si is between 0.1 to 0.3 weight %. 
     
     
       3. The powder according to  claim 1 , wherein the content of Mn is from 0.1 to 1.1 weight. 
     
     
       4. The powder according to  claim 1 , wherein the content of Ni is from 35.3 to 36 weight %. 
     
     
       5. The powder according to  claim 1 , wherein the content of Mo is from 6.4 to 6.6 weight %. 
     
     
       6. The powder according to  claim 1 , wherein the content of N is of from 0.35 to 0.60 weight %. 
     
     
       7. The powder according to  claim 1 , wherein said powder comprises less than or equal to 200 ppm O. 
     
     
       8. The powder according to  claim 1 , wherein the content of Cr is from 26.7 to 27.8 weight %. 
     
     
       9. The powder according to  claim 1 , wherein the content of N is of from 0.32 to 0.38 weight %. 
     
     
       10. The powder according to  claim 1 , comprising an austenitic alloy having the following composition in weight %:
 C less than or equal to 0.03; 
 Si 0.1 to 0.3; 
 Mn 0.1 to 0.5; 
 P less than or equal to 0.04; 
 S less than or equal to 0.05; 
 Cr 26.7 to 27.8; 
 Ni 35.3 to 36; 
 Mo 6.4 to 6.7; 
 N 0.35 to 0.60; 
 Cu less than or equal to 0.4; 
 O less than or equal to 200 ppm; 
 balance Fe and unavoidable impurities. 
 
     
     
       11. A method of manufacturing a HIP:ed object wherein the HIP:ed object is a tube, the method comprising the steps of:
 a) providing a form defining a shape of a billet or a hollow or a bar; 
 b) providing a powder as defined in  claim 10 ; 
 c) filling at least a portion of said form with said powder; 
 d) subjecting said form to hot isostatic pressing at a temperature, at an isostatic pressure, and for a predetermined time so that particles of the powder bond metallurgically to each other; and 
 e) hot working the obtained billet, hollow or bar. 
 
     
     
       12. A method of manufacturing a HIP:ed object wherein the HIP:ed object is a tube, the method comprising the steps of:
 a) providing a form defining a shape of a billet or a hollow or a bar; 
 b) providing a powder as defined in  claim 1 ; 
 c) filling at least a portion of said form with said powder; 
 d) subjecting said form to hot isostatic pressing at a temperature, at an isostatic pressure, and for a predetermined time so that particles of the powder bond metallurgically to each other; and 
 e) hot working the obtained billet, hollow or bar. 
 
     
     
       13. The method according to  claim 12 , wherein the hot working process is extrusion. 
     
     
       14. The method according to  claim 12 , wherein the method comprises a cold working step which is performed after the hot working step. 
     
     
       15. The method according to  claim 14 , wherein the method optionally comprises a heat treatment step which is performed either after the hot working step or after the cold working step. 
     
     
       16. The method according to  claim 15 , wherein the heat treatment process is solution annealing. 
     
     
       17. A HIP:ed object, comprising an austenitic alloy having the following composition in weight %:
 C less than or equal to 0.03; 
 Si 0.1 to 0.5; 
 Mn 0.1 to 2.0; 
 P less than or equal to 0.01; 
 S less than or equal to 0.05; 
 Cr 26.7 to 28; 
 Ni 35 to 36; 
 Mo 6.1 to 6.7; 
 N 0.32 to 0.60; 
 Cu less than or equal to 0.4; 
 balance Fe and unavoidable impurities. 
 
     
     
       18. The HIP:ed object according to  claim 17 , wherein the content of Si is between 0.1 to 0.3 weight %. 
     
     
       19. The HIP:ed object according to  claim 17 , wherein the content of Mn 0.1 to 1.1 weight %. 
     
     
       20. The HIP:ed object according to  claim 17 , wherein the content of Ni is from 35.3 to 36 weight %. 
     
     
       21. The HIP:ed object according to  claim 17 , wherein the content of Mo is from 6.4 to 6.6 weight %. 
     
     
       22. The HIP:ed object according to  claim 17 , wherein the content of N is of from 0.35 to 0.60 weight %. 
     
     
       23. The HIP:ed object according to  claim 17 , wherein said object comprises less than or equal to 200 ppm O. 
     
     
       24. The HIP:ed object according to  claim 17 , wherein the HIP:ed object is a tube. 
     
     
       25. A welded tube, comprising two or more tubes according to  claim 24 , wherein the two or more tubes are joined by welding. 
     
     
       26. An umbilical, comprising a plurality of tubes according to  claim 24 . 
     
     
       27. A HIP:ed object according to  claim 17 , comprising an austenitic alloy having the following composition in weight %:
 C less than or equal to 0.03; 
 Si 0.1 to 0.3; 
 Mn 0.1 to 0.5; 
 P less than or equal to 0.04; 
 S less than or equal to 0.05; 
 Cr 26.7 to 27.8; 
 Ni 35.3 to 36; 
 Mo 6.4 to 6.7; 
 N 0.35 to 0.60; 
 Cu less than or equal to 0.4; 
 O less than or equal to 200 ppm; 
 balance Fe and unavoidable impurities. 
 
     
     
       28. A method of manufacturing a HIP:ed object according to  claim 17 , comprising the steps of:
 a) providing a form defining at least a portion of the shape of said object; 
 b) providing a powder comprising an austenitic alloy having the following composition in weight %:
 C less than or equal to 0.03; 
 Si 0.1 to 0.5; 
 Mn 0.1 to 2.0; 
 P less than or equal to 0.04; 
 S less than or equal to 0.05; 
 Cr 26.7 to 28; 
 Ni 35 to 36; 
 Mo 6.1 to 6.7; 
 N 0.32 to 0.60; 
 Cu less than or equal to 0.4; 
 balance Fe and unavoidable impurities; 
 
 c) filling at least a portion of said form with said powder; 
 d) subjecting said form to hot isostatic pressing at a temperature, at an isostatic pressure, and for a time so that particles of the powder bond metallurgically to each other. 
 
     
     
       29. The method according to  claim 28 , wherein the obtained HIP:ed object is heat treated. 
     
     
       30. The method according to  claim 28 , wherein the obtained HIP:ed object is hot worked.